Rapidly Growing Mycobacteria Infection Research Articles

Human environment around the world surrounded by rapidly growing mycobacteria (RGM)

Aims and Objective: The rapid growth of Mycobacteria (RGM) is a member of Non-tuberculous Mycobacterium that are environmental and opportunistic pathogens whose role in human disease is increasingly recognized. RGMs are highly found in various natural and man-made environmental resources. They can be opportunistically transmitted to humans through contaminated water sources and cause their infectious pulmonary and extrapulmonary infectious diseases. Misdiagnosis of this type of mycobacterium can lead to destructive results. As a result, improper treatment Faced with it can lead to recurrent infections as well as drug resistance. Methods: The aim of this study was to review the existing studies on the prevalence of RGMs between 1990-2017 in worldwide. Data on the prevalence of RGM infection were collected from databases such as PubMed, Web of Science, Cochrane Library, Embase, Scopus, and other scientific databases. Results: In Asia, 776 cases were reported. Among these, the M. furtuitum 23.32% (181,776), and M. chelonae 18.04%(140,776) were the most prevalence, respectively. Also, 105 cases reported in Africa, with the highest prevalence cases being M. fortuitum 46.67%(49,105), M. neoaurium 14.29%(15,105), and M. septicum 8.57% (9,150), respectively. On the other hand, 1363 cases were reported throughout Europe. Among these, the M. furtuitum 30.37% (414,1363), M. chelonae 18.86%(257,1363), and M. peregrinum 13.94%(190,1363) were the most prevalence, respectively. In the United States, 237 cases of RGM were reported, which the highest prevalence was related to the genus M. chelonae 25.32%(60,237), M. mucogenicum 23.63%(56,237) and M. furtuitum 22.36%(53,237), respectively. Also, in Australia 120 cases were observed, with the highest prevalence in M. fortuitum 49.17%(59,120), M. septicum 21.67%(26,120), and M. chelonae 8.33%(10,120), respectively. Conclusion: Given the increasing prevalence of RGMs in different environments, it seems necessary to implement more infection control strategies, appropriate diagnostic methods and control guidelines for NTM diseases. It can be said that we need to increase the quality of diagnostic reference methods and more accurate measures to prevent and control RGM infections.

Endophthalmitis caused by Mycobacterium houstonense: case report

BackgroundMycobacterium houstonense is rapidly growing mycobacteria (RGM) that belongs to M. fortuitum group. So far, there have been few associated reports of human diseases induced by M. houstonense worldwide.Case presentationWe present a delayed-onset postoperative endophthalmitis caused by M. houstonense after glaucoma drainage implant (GDI) surgery. The ocular infection lasted for 2 months without appropriate treatment that developed into endophthalmitis and the patient underwent an emergency enucleation.ConclusionImplant erosion and a delay in diagnosis of ocular infection could lead to irreversible damage as observed in our case. Ophthalmologists should be alert for ocular RGM infection, and prompt laboratory diagnosis with initiation of effective multidrug therapy might prevent loss of vision.

Nontuberculous mycobacterial infection in a tertiary care center in Mexico, 2001–2017

IntroductionNontuberculous mycobacteria (NTM) comprise several pathogens with a complex profile of virulence, diverse epidemiological and clinical patterns as well as host specificity. Recently, an increase in the number of NTM infections has been observed; therefore, the objective of this study was to evaluate the clinical characteristics and outcomes of these infections. MethodsWe included patients with NTM infections between 2001–2017 and obtained risk factors, clinical features and outcomes; finally, we compared this data between slowly growing (SGM) and rapidly growing mycobacteria (RGM). ResultsA total of 230 patients were evaluated, 158 (69%) infected and 72 (31%) colonized/pseudoinfected. The average annual incidence in the first 11 years of the study was 0.5 cases per 1000 admissions and increased to 2.0 cases per 1000 admissions later on. The distribution of NTM infections was as follows: bloodstream and disseminated disease 72 (45%), lung infection 67 (42%), skin and soft tissue infection 19 (12%). Mycobacterium avium complex was the most common isolate within SGM infections, and HIV-infected patients were the most affected. Within RGM infections, M. fortuitum was the most common isolate from patients with underlying conditions such as cancer, type-2 diabetes mellitus, presence of invasive devices, and use of immunosuppressive therapy. We did not find significant differences in deaths and persistent infections between disseminated SGM infection when compared to disseminated RGM infection (42% vs. 24%, p=0.22). However, disseminated SGM infection required a longer duration of therapy than disseminated RGM infection (median, 210 vs. 42 days, p=0.01). NTM lung disease showed no significant differences in outcomes among treated versus non-treated patients (p=0.27). ConclusionsOur results show a significant increase in the number of Non-tuberculosis-mycobacteria infections in our setting. Patients with slow-growing-mycobacteria infections were mainly persons living with human immunodeficiency virus . Older patients with chronic diseases were common among those with rapidly-growing-mycobacteria infections. For non-tuberculosis-mycobacteria lung infection, antibiotic therapy should be carefully individualized.

Rapidly-growing mycobacterial infection: a recognized cause of early-onset prosthetic joint infection

BackgroundProsthetic joint infection (PJI) is a major complication of total hip and total knee arthroplasty (THA, TKA). Although mycobacteria are rarely the causative pathogens, it is important to recognize and treat them differently from non-mycobacterial infections. This study aimed to compare the clinical characteristics, associated factors and long-term outcomes of mycobacterial and non-mycobacterial PJI.MethodsWe conducted a retrospective case-control study of patients aged ≥18 years who were diagnosed with PJI of the hip or knee at Siriraj Hospital from January 2000 to December 2012. Patient characteristics, clinical data, treatments and outcomes were evaluated.ResultsA total of 178 patients were included, among whom 162 had non-mycobacterial PJI and 16 had mycobacterial PJI. Rapidly growing mycobacteria (RGM) (11) and M. tuberculosis (MTB) (5) were the causative pathogens of mycobacterial PJI. PJI duration and time until onset were significantly different between mycobacterial and non-mycobacterial PJI. Infection within 90 days of arthroplasty was significantly associated with RGM infection (OR 21.86; 95% CI 4.25–112.30; p < .001). Implant removal was associated with improved favorable outcomes at 6 months (OR 5.96; 95% CI 1.88–18.88; p < .01) and 12 months (OR 3.96; 95% CI 1.15–13.71; p = .03) after the infection.ConclusionsRGM were the major pathogens of early onset PJI after THA and TKA. Both a high clinical index of suspicion and mycobacterial cultures are recommended when medically managing PJI with negative cultures or non-response to antibiotics. Removal of infected implants was associated with favorable outcomes.

86 Molecular typing of rapidly growing mycobacteria (RGM) in patients with cystic fibrosis (CF)

Objectives To perform molecular typing of clinical strains of RGM isolated from the lower respiratory tract of CF patients with persistent, transient and intermittent infections. Secondary, to assess whether chronic infections are sustained by the same bacterial species, over time. Methods Twenty-three patients, out of the 793 followed at the Regional Reference Centre for Cystic Fibrosis of Milan, have a persistent RGM infection, and 19 show an intermittent infection. From October 2013 to October 2014, 65 strains were isolated and typed by gene sequencing of the rpo B gene. The gene sequences obtained were compared to those already present in the GenBank database to discriminate subspecies of RGM. Results Molecular typing of 46 strains (at two different follow-up times: T1, T2), isolated from 23 patients with chronic RGM colonization, reveals that chronic infection are sustained, in 100% of cases, by MAC (61% M. abscessus sensu stricto, 26% M. bolletii and 13% M. massiliense ), and species identified at T1 is the same identified at T2. In 19 patients, the intermittent infection is sustained by different species of RGM: 37% M. chelonae, 26% M. abscessus sensu stricto, 26% M. bolletii, 5.5% M. fortuitum and 5.5% M. massiliense. Conclusion The chronic infections are sustained by MAC, with a higher prevalence of M. abscessus sensu stricto, and that species acquired at T1 persists over time. Intermittent infections are sustained by M. chelonae, M. fortuitum and MAC. Further correlation studies between the clinical course of the pulmonary disease and the presence of MAC different subspecies are recommended in order to create appropriate therapeutic schemes.

Direct identification of Mycobacterium abscessus through 16S rDNA sequence analysis and a citrate utilization test: A case report.

A growing number of nontuberculous mycobacteria infection cases, especially those caused by rapidly growing mycobacteria (RGM), have been reported in the past decade. Conventional methods for mycobacteria diagnosis are inefficient and easily lead to misdiagnosis. New detection methods, such as gene sequencing, have been reported but are not widely used. The aim of the present case report was to provide a quick and exact method of identifying Myobacterium abscessus (M. abscessus) infections. The particular case reported in this study initially manifested as hyperglycemia and papules in the right leg. Routine cultures for fungus were repeatedly negative. However, cultures of the purulent material under aerobic cultivation for five days yielded a rapidly growing, nontuberculous mycobacterium. A Ziehl-Neelsen staining of this mycobacterium revealed the presence of acid-fast bacilli that were finally identified as M. abscessus through 16S rDNA sequence analysis and a citrate utilization test. The current report may help other clinicians to make a quick and accurate diagnosis of RGM infection.

Skin and Soft Tissue Infection due to Rapidly Growing Mycobacteria: Case Series and Literature Review

BackgroundNontuberculous mycobacteria (NTM) are ubiquitous in soil and water. Most NTM cause disease in humans only rarely unless some aspect of host defense is impaired. Recently, rapidly growing mycobacteria (RGM) is not uncommon, and the prevalence of RGM infection has been increasing. RGM causes a wide spectrum of pulmonary and extrapulmonary diseases and has been shown as an important source for opportunistic infection.Materials and MethodsWe report 5 patients of skin and soft tissue infection due to RGM in tertiary medical center in Jeju Island and analyzed 21 patients of skin and soft tissue infection due to RGM in Republic of Korea. Clinical, microbiological and epidemiological data were collected from each patient. NTM isolates were identified using conventional and molecular methods including 16S rDNA gene sequencing.ResultsThe mean age of the RGM patients (n=26) was 54.9 ± 15.9 years and 73% were women. Mycobacterium fortuitum complex was the most common (12/26). Antimicrobial resistance for clarithromycin and quinolone were 12% and 60%, respectively. Clarithromycin based therapy was done in 46%. The mean duration of treatment was 21.2 ± 8.7 weeks.ConclusionsMany cases can be cured after therapy for 4-7 month with at least 2 or 3 antibiotics according to in vitro susceptibility. Recent increasing of NTM cases suggests that species and subspecies identification is epidemiologically important, especially related to medical procedure, and surgery.

Management of Infections with Rapidly Growing Mycobacteria after Unexpected Complications of Skin and Subcutaneous Surgical Procedures

BackgroundInfection caused by rapidly growing mycobacteria (RGM) is not uncommon, and the prevalence of RGM infection has been increasing. Clinical diagnosis is difficult because there are no characteristic clinical features. There is also no standard antibiotic regimen for treating RGM infection. A small series of patients with RGM infections was studied to examine their treatments and outcomes.MethodsA total of 5 patients who had developed postoperative infections from January 2009 to December 2010 were retrospectively reviewed. Patients were initially screened using a mycobacteria rapid screening test (polymerase chain reaction [PCR]-reverse blot hybridization assay). To confirm mycobacterial infection, specimens were cultured for nontuberculous mycobacteria and analyzed by 16 S ribosomal RNA and rpoB gene PCR.ResultsThe patients were treated with intravenous antibiotics during hospitalization, and oral antibiotics were administered after discharge. The mean duration of follow-up was 9 months, and all patients were completely cured of infection with a regimen of a combination of antibiotics plus surgical treatment. Although none of the patients developed recurrence, there were complications at the site of infection, including hypertrophic scarring, pigmentation, and disfigurement.ConclusionsCombination antibiotic therapy plus drainage of surgical abscesses appeared to be effective for the RGM infections seen in our patients. Although neither the exact dosage nor a standardized regimen has been firmly established, we propose that our treatment can provide an option for the management of rapidly growing mycobacterial infection.

Rapidly Growing Mycobacteria Infection in Patients with Cancer

Rapidly growing mycobacteria (RGM) have been associated with various clinical syndromes in immunocompetent and immunocompromised hosts. The risk factors and outcomes of RGM infection in patients with cancer have not been clearly defined. Data were derived from 2 distinct sources. Demographic and clinical data were collected for all patients with cancer at Memorial Sloan-Kettering Cancer Center with a culture positive for RGM from January 1999 through December 2008. We also reviewed the literature for studies describing RGM infection in patients with cancer. During the 10-year period, 28 patients with cancer at Memorial Sloan-Kettering Cancer Center had cultures positive for RGM. Most cases occurred in patients with solid tumors and were confined to the lung. A review of the literature identified 313 additional patients with cancer and RGM infection. Combining our series data with cases from the literature, we defined 3 distinct syndromes: pulmonary disease, which occurred in 158 patients (47%); bloodstream infection, occurring in 151 patients (45%); and disseminated infection involving at least 1 end organ, affecting 26 persons (8%). The syndromes differed by age of onset, underlying cancer, main RGM species, and outcome. Persons with bloodstream infection typically were young and had an excellent outcome; those with disseminated infection were older, had pronounced immunosuppression, and had a very poor prognosis. RGM infections in patients with cancer comprise 3 distinct disorders with different risk factors, predominant mycobacterial species, and prognoses. In turn, the approach to management, including number and duration of antimycobacterial drugs, may be fundamentally different for various patients with cancer who receive a diagnosis of RGM infection.

Diagnosis and Treatment of Infections Caused by Rapidly Growing Mycobacteria

Rapidly growing mycobacteria (RGM) are ubiquitous environmental organisms capable of causing a wide variety of infections in humans. The prevalence of RGM infections appears to be increasing, although exact incidence rates are unknown. Although some risk factors for pulmonary RGM infection have been determined, the specific host factors predisposing to disease in the majority of cases are not clear. Significant advances in molecular methods of mycobacterial identification have led to isolation of more varieties, changes in taxonomy, and more rapid and accurate diagnosis of RGM from clinical isolates. Despite significant advances in the field, diagnosing and treating RGM pulmonary infections remain complicated. Current guidelines are based on the most commonly encountered NTM. Their applicability to less frequent RGM isolates has not been definitively established. Treatment often requires multiple antimicrobial agents for prolonged periods of time, with varying degrees of success and significant associated morbidity.

Prosthetic Joint Infection Due to Rapidly Growing Mycobacteria: Report of 8 Cases and Review of the Literature

Prosthetic joint infection (PJI) due to rapidly growing mycobacteria (RGM) is only occasionally encountered in clinical practice. Therefore, the optimal clinical management for this condition is unknown. The medical records of patients who had PJI due to RGM during 1969-2006 were reviewed to summarize its clinical characteristics, treatment, and outcome. Eight patients developed 9 episodes of PJI (7 episodes involving the knee and 1 each involving the hip or elbow) due to RGM at a median of 312 weeks (range, 1-170 weeks) after prosthesis implantation. Patients presented with joint pain (7 patients), joint swelling (7 patients), and fever (3 patients), accompanied by an elevated erythrocyte sedimentation rate (median, 70.5 mm/h) and C-reactive protein level (median, 6 mg/dL). Mycobacterium chelonae (n=3), Mycobacterium abscessus (n=2), Mycobacterium fortuitum (n=3), and Mycobacterium smegmatis (n=1) were isolated from the 9 infected joints. Seven of 9 prostheses were resected, whereas 2 were retained after surgical debridement. Six of 8 patients received > or = 1 active antimicrobial agent for at least 6 months. During a median follow-up period of 33 weeks (range, 2.6-326 weeks) after surgical intervention, no clinical or microbiological relapses were observed. Reimplantation was performed successfully for 2 of 6 patients who underwent resection arthroplasty. The 2 patients with retained prosthesis continued to receive prolonged courses of suppressive antimicrobial therapy. RGM is a rare cause of PJI that should be suspected in patients with negative results of routine bacterial cultures. The combination of resection arthroplasty and antimicrobial therapy is the preferred approach. However, in cases involving retained prosthetic components, RGM infection may be suppressed with lifelong courses of effective antibiotic therapy.

Alpha-1-antitrypsin (AAT) anomalies are associated with lung disease due to rapidly growing mycobacteria and AAT inhibits Mycobacterium abscessus infection of macrophages

Rapidly growing mycobacteria (RGM) are ubiquitous in the environment but cause lung disease in only a fraction of exposed individuals. This variable susceptibility to disease implies vulnerability to RGM infection due to weakness in host defense. Since most persons who contract RGM lung disease have no known host defense defect, it is likely that uncharacterized host deficiencies exist that predispose to RGM infection. Alpha-1-antitrypsin (AAT) is a host factor that may protect individuals from respiratory infections. Therefore, we assessed AAT protein anomalies as a risk factor for RGM lung disease. In a cohort of 100 patients with RGM lung disease, Mycobacterium (M.) abscessus was the most prevalent organism, isolated in 64 (64%) subjects. Anomalous AAT proteins were present in 27% of the cohort, which is 1.6 times the estimated prevalence of anomalous AAT proteins in the United States population (p=0.008). In in vitro studies, both AAT and a synthetic inhibitor of serine proteases suppressed M. abscessus infection of monocyte-derived macrophages by up to 65% (p<0.01). AAT may be an anti-RGM host-defense factor, and anomalous AAT phenotypes or AAT deficiency may constitute risk factors for pulmonary disease due to RGM.